1. Department of Experimental Hematology, Hannover Medical School, 30625 Hannover, Germany.
2. Molecular Pathology Unit, Center for Cancer Research, and Center for Computational and Integrative Biology, Massachusetts General Hospital, Charlestown, MA 02129.
3. Biological and Biomedical Sciences Program, Harvard Medical School, Boston, MA 02115.
4. Department of Pathology, Harvard Medical School, Boston, MA 02115.